Work clamp for buttonhole-sewing machines



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WORK CLAMP FOR BUTTONHOLE4 SEWING IAQHINES Fired Nov. 18,'1921 s'v sneetssnnj 1` ness.'

April 20;, 192e. 1,581,214

4a. T. Lay/Eemsv I .11011K cmu ronvu'r'ronmoLz 'sauna ncnnss 1111.11 mv. 1e'. 1921 s sheets-sheet 2 April 20, 1926. 1.581,2"14- B. T. LEVEQUE WORK CLAMP P 'OR BUTTONHOLE SEWIN-G MACHINE-S t Filed Nov. 1s. 1921 s shuts-snm s Patented pr. 20, 1926'.r

BERNARD T. LEVEQUE, or WENHAM, AMASSAcirusn'rrs;,Assistant To UNITEnsgon MACHINERY CORPORATION,y

New. JERSEY.

0F] www, New; A @atomica-@ WoRK CLAMP FCR RUr'roNMore-snwINe'Y MACniNNs.

Application filed November'lS,` 1921;.v SleralNa 516,183.

To all whom z'z. may concern.' Y

Be it known that I, BERNARD T. LEVEQUE,

a citizen of the United States, residing at lVenham, vin the county of Esse-X and State of Massachusetts, have invented certain new and useful Improvements in Work Clamps forButtonhole-Sewing Machines; and I do -herebydeclare the following to be a full,

clear, and exact description o-f the invention,

such asv will enable others skilled in the art to which it appertains to make andA use the same. y

Theinvention relates to work holding and thread. .cutting mechanism for `buttonhole sewing Y machines.

The invention provides simple and efficient mechanism for opening and closing the work engaging jaws of the work clamp, for

spreading the jaws to hold the Vwork taut at the Vpoint where the buttonhole is made and for Vactuating the'thread cutter with which one of the jaws is provided, and it comprises the features of construction and combination of parts hereinafter described and referred to in the claims. j

Vhile not confined in its' application to such machinefthe invention is Vintended primarily as an improvement in the machine shown and described in application Serial No. `255,849, filed September 26, 1918, and has been shown and will be further eX- plained as applied to this machine.

In the drawings Fig. l is a side elevation showing so much of the sewing machine of said patent as is necessaryto show .the application of the invention thereto, Fig. 2 isa sectional elevation, and Fig. Sis a planview ofthe parts shown in Figs. l and 2.

The machine to which the invention has been applied comprises in general a stitch forming mechanism which is mounted to ro- K tate while sewing about the eye and bar end of the buttonhole and which includes an upper needle 2, an under needle 4 and a looper 6,'a small reciprocating cutter 8 which acts" on the work just ahead of the sewing point to progressively cut the buttonhole slit during the sewing, and a work clamp which is movable lengthwise and laterally of the buttonhole and which carries a thread cutter for cutting and holding the upper needle thread at the completion of the buttonhole. i parts ofthe work clamp are carried on the The Y clamp., carriage` which comprises` apcurved plate 10 carriediuponfsupporting armsone of which, indicated at 12,-is mountedto slide and turn 01,1 the. cam shaf-t`l4. The-carriage is moved lengthwise of: the buttonhole by. a feed cam Y16 secured to thecam shaft and provided witha cam vgroove enga-ging a roll carrledybyY alever 18, the upper end of which f 1s connectedv by a link 2O with the carri-age. f

The 'carriage is moved laterally bya cam groove formed ina flange onfthe feedc'am which engagesI a roll on tlielever l24. The upper end of the lever is connectedby a link 26 with a stud 28 projecting from'the carriage The stud is' arranged Vto slide through the end of the link during the backwardr and forward movement of the carri-age and this end of the link is provided lwith a,

vertical projection 30 arranged tol move laterally in a fixed guidewayQ on the machine, frame.

The means .for grippingor clamping the work upon the carriagecomprises.the work supporting plates 34 and the vertically movable vclamping jaws 36 and 38. The plates and jaws are shaped to embrace the path of action of the stitch forming mechanism and lengthwise of the buttonhole, since it y.ifs desirable to hold theV work taut in this direction during the progressive cutting ofthe buttonhole slit- The fro-nt jaw 36is pivotally supported in the arms of an yoke Vformed on the 'forward end ofthe clamp lever 40 whilethel rear clamping jaw 38 is pivotally supported in the arms of ai yoke formed on the forward end of a bar 42. which is mounted to slide in a bearing formed in the lever 40 and 4is forced yieldingly forward by a spring 44. The forwardmovement o-f the bar 42`is limited by a collar 46 secured to the bar and ar-y the hub. lIhe studs are `held in positionin the lugs by spring pressed latching balls 52 arranged toengage grooves 5,4 in the studs.' The'studs may be readily withdrawn from ,80 the jaws are mounted :for relativemovement the hub of the clamping lever to permit the removal and replacement of the lever and the parts carried thereby and when withdrawn are heldin retracted position by engagement of the latching balls with the grooves 56 in the studs. rl`he clamp lever is provided with a rearwardly projecting arm the rear end of which lies in a clevis formed by two plates 58 and 60 on the upper end of a vertically movable stud 62. The stud is forced upward and thus in a direction to close the clamp and press the clamping jaws 86 and 38 firmly against the work by a spring 64. The means for opening and closing the clamp comprises a bell crank lever 66, one arm of which is arranged to engage the upper plate 58 of the stud 62, and the other arm of which carries a roll engaged by a cam 68 which is driven from the cam shaft 14. rIhis construction permits the clamp lever and parts carried thereby to be readily removed and replaced when the parts are held in clamp opening position as indicated in Fig. l.

The mechanism for relatively moving the jaws 86 and 88 to stretch the work and hold it taut is carried on the clamp lever and is operated from the clamp opening and closing mechanism with which it is so connected as not to interfere with the removal and replacement of the lever. As shown this mechanism comprises toggle links 70, one of which is pivoted to the hub of the lever 40 and the other of which is pivoted to a collar 72 adjustably held on the end of the bar 42 by the nuts 74. The toggle is connected by a link 7 6 with a lever 78 which is pivoted on an arm rising from the lever 40 and is pro vided at its rear end with a clevis 8O embracing a stud 82 which projects from the side of the clamp closing lever 66. The -stud 82 may be in the form of an eccentric sleeve which is secured in adjusted position on a stud 84 by a nut 86. When the horizontal arm of lever 66 is raised to close the clamp the toggle linksand connected lever 7 8 move with the clamp lever 40 until the jaws 36 and 38 engage the woik and then continued upward movement of the lever 66 into the position indicated in Fig. 2 rocks the lever 7 8 to straighten the toggle links 7() and thus draw the bar 42 and jaw 88 rearward to stretch the work lengthwise of the buttonhole. The movement given to the lever 7 8 is su'iicient to carry the knuckle of the toggle below the line of centers as indicated in Fig. 2 so that the toggle firmly locks the jaw in its retracted position during the sewing of the buttonhole. When the lever 66 is operated to open the clamp at the completion of the buttonhole the first downward movement of its horizontal arm rocks the lever 78 to break the toggle so that the jaw 38 is re turned to its forward position by the spring 44. After the jaw has been thus returned the continued movement of the lever 66 depresses the stud 62 and rocks the lever 40 againstthe pressure of the spring 64 to open the clamp as indicated in Fig. l.

lhe jaw 86 of the work clamp is provided with a thread c-utter and holder in the forni of a lever 88 arranged to pass between two plates 90 and 92 en the jaw and to cooperate therewith in severing and holding the upper needle thread. The mechanism for actuating the thread cutter and holder is mounted on the clamp lever 40 to be removed and replaced therewith and is actuated from the clamp opening and closing mechanism through the jaw spreading mechanism. As shown the thread cutter and holder is coiineeted by a twisted link 94 with the vertical arm of a three-arm lever 96 which is pivoted on the saine pivot which supports the lever 78 and is provided with an arm extending laterally over the front end of this lever and also with an arm extending rearwardly into position to engage the laterally projecting end ef the stud 84 on the lever 66. The

thread cutting and holding lever 88 is held in open or closed posit-ion by a leaf spring 98, the end of which is shaped to engage either one ed'e or the other of the vertical arm of lever 96.

`When the lever 66 is moved at the completion of a buttonhele te return the jaw 38 to forward position and open the clamp the movement of the lever 7 8 which precedes the opening of the clamp will rock the three-arm lever 96 into the position indicated in Figs. l and 8 and thus swing the thread cutting and holding lever 88 across the needle path and into position between the plates and 92, thus severing and holding the upper needle thread just prior to the opening of the clamp. rl`he outer end of the spring 98 will now bear against the rear edge of the vertical arm of the lever 96 and retain the thread cutting and holding lever in this position, when the lever 66 is moved into the position indicated Y in Fig. 2 to close the clamp and spread the jaws 86 and 88. rlthe lever 88 will, therefore, continue to hold the thread during the sewing of the initial stitches of the buttonhole seam and during the first part of the forward travel of the clamp carriage. The forward movement of the clamp carriage will bring the cam surface iOO on the threearm lever 96 into engagement with the stud 84 on the arm 66 se that the lever will be rocked to withdraw the thread holding and cutting lever 88 from between the plates 96 and 92 and into position to again act upon the needle thread. he lever will be held in this open position until the completion of the buttonhole and until the lever 66 is again operated to open the clamp, by the engagement of the curved end of the spring 98 with the forward edge of the vertical arm of the three-arm lever 96.

In order that the clamp may be convenliu iently opened manually an eccentric l02 is secured upon a rock shaft 104 and is arranged to engage and lift the forward arm of the clamp lever 40. The rock shaftis mounted in a bearing on the clamp carriage and is provided with an operating handle 10G arranged within convenient reach of the operator.

lVhile it is preferred to employ the specilic construction and arrangement of parts shown and described in embodying the invention in the machine of the patent above referred to it will bek understood that `this construction and arrangement is not essential to the broader features of the invention and may be varied or modified as found desirable or best suited to the construction and mode of operation of theinaohine in which it is to be embodied.

I claim:

l. A work clamp comprising a clamp lever, mechanism for automatically actuating the lever to open and close the clamp, work engaging jaws carried by the lever, and mechanism for spreading the jaws mounted on the lever and operated from the lever actuating mechanism. f

2. A work clamp; comprising a clamp lever, mechanism for actuating the lever to open and close the clamp, work engaging jaws carried b the lever, a toggle on the lever for spreading the jaws, and means for operating the toggle from the lever actuating mechanism.

3. A work clamp comprising front and rear work engaging jaws, a toggle forspreading the jaws lengthwise of the buttonhole, and mechanism for closing the jaws and then straightening the toggle, and for breaking the toggle and then opening the jaws. i

4. A work clamp comprising a clamp lever, a work engaging jaw on the forward end of the lever, a bar mounted to slide in the lever, a work engaging jaw on the forward end of the bar, a toggle connecting the bar and lever, means for straightening the toggle when the jaws are closed and for breaking the toggle when the jaws are raised.

5. A work clamp comprising' a clamp lever, work engaging jaws carried on the lever, a spring operated clevis engaging the rear end of the lever, a cam operated lever for depressing the clevis to open the clamp,

jaw spreading mechanism including a clevis mounted on the clamp lever, and a stud on the cam lever embraced by the latter clevis.

6. A work clamp comprising a clamp lever, work engaging jaws carried on the lever, a cani operated lever for actuating the clamp lever, jaw spreading mechanism mounted on the clamp lever, a thread cutter on one of the jaws, connections for actuating the cutter from the jaw spreading mechanism to cut the thread and from the cam lever to release the thread.

7. A traveling work clamp comprising a clamp lever, work engaging jaws carried on the lever, a thread cutter and holder on one of the jaws, mechanism for automatically actuating the lever to open and close the clamp, and mechanism for actuating the cutter and holder mounted on the lever and operated from the lever actuating mecha*- nisin to out and hold the thread and operated during the travel of the clamp to release the thread. Y f

8. Ak work clamp comprising a clamp lever, work engaging jaws carried on the lever, mechanism for actuating the lever to open and close the clamp, mechanism carried on the'lever for spreading the jaws, and a thread cutter on one of the jaws operated from the spreading mechanism.

9. Aq work clamp comprising a clamp lever, work engaging jaws carried on the lever, mechanism for actuating the lever to.`

open and close the clamp, jaw spreading mechanism on the lever operated by the lever actuating mechanism, and a thread cutter on one of the jaws operated .from the spreading mechanism. j

l0. A work clamp comprising a clamp car iage, a clamp lever on the carriage, work engaging jaws carried on the lever, a cam operated lever for actuating the cla-mp lever, jaw spreading mechanism on the clamp in cluding a clevis, a st-ud on the cam lever em braced by the clevis, a thread cutter on one of the jaws, a lever for actuating the thread cutter mounted on theclamp lever and operated to cut the thread by the movement of the clevis preceding the opening of the clamp and operated from the camlevor to retract the cutter during the forward travel of the carriage. f

11. A work clamp comprising a clamp lever, work engaging jaws carried on the lever, a clevis embracing the rear end of the lever, a spring for forcing the clevis upward and endwise movable pivot studs for removably engaging bearings in the lever.

12. A traveling work clamp comprising a clamp lever, a thread cutter and holder on the lever, a clamp operating lever, connections through which motion is ltransmitted from the clamp operating lever to the thread cutter and holderto cut and hold the thread and thereafter release the thread during the travel of the clamp, a rotary cam shaft, and a cam on the shaft for operating the clamp operating lever.

v BERNARD T. LEVEQUE 

